JP2010015778A - Vacuum electromagnetic contactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an electromagnetic contactor which prevents burnout of an electromagnetic solenoid section caused by abnormal heat generation and does not automatically return when electric conduction of an electromagnetic coil is blocked by the abnormal heat generation. <P>SOLUTION: In the vacuum electromagnetic contactor wherein the electromagnetic coil 9 of an electromagnetic solenoid 6 is excited and contacts 1a, 1b of a vacuum valve 1 are turned on by making use of suction force for sucking a moving member 5, a shape memory spring 10 is arranged in the vicinity of the electromagnetic solenoid 6, and an abnormality detection switch 11 is arranged on a control circuit of the electromagnetic coil 9. When the electromagnetic coil 9 abnormally generates heat, the shape memory spring 10 is displaced by heat generated temperature, an abnormality display lever 14 is turned from a normal position to an abnormal position on the basis of this displacement, and excited current of the electromagnetic coil 9 is blocked by an operation of the abnormality detection switch 11. Such the blocked state is retained in spite of reduction of heat generated temperature until the abnormality detection lever 14 is returned to the normal position. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vacuum electromagnetic contactor that is incorporated in, for example, a high-voltage switchboard and used as a switching controller for a high-voltage motor, a power factor improving capacitor, and the like. This relates to the prevention of burnout of the solenoid part.

As a conventional technique for preventing burnout of an electromagnetic solenoid, for example, an apparatus as shown in FIG. 6 is known. FIG. 6 shows a solenoid control valve that is used in a fluid conduit to control the opening and closing of the flow path, and shows a cross section of the main part thereof. When the coil 21 of the solenoid is not energized, the blanker 22 is driven upward by the force of the spring 23 and the control valve is open. When the coil 21 is energized, the plunger 22 is lowered by the attraction force of the coil 21, and the valve portion 24 at the tip is seated on the valve seat 25 so that the valve is closed as shown in FIG. In the upper part of the apparatus, there are provided a switch 26 made of a bimetal or a shape memory alloy and a switch contact 27 which are displaced by sensing the ambient temperature. The switch 26 is connected in series to the drive circuit of the coil 21 and is “normally closed” as indicated by a dotted line.
In such a configuration, when the energization time becomes long for some reason while the coil 21 is energized, and the coil 21 generates heat and the ambient temperature rises, the switch 26 senses and displaces it, It leaves | separates from the switch contact 27 and the electricity supply to the coil 21 is interrupted | blocked (state of FIG. 4). When the abnormal heat generation is stopped by the interruption of the energization and the temperature decreases, the switch 26 is restored and the electromagnetic solenoid can be automatically energized (for example, see Patent Document 1).

JP-A-4-194353 (page 3-4, FIG. 1)

  When the electromagnetic solenoid as described above is applied to an electromagnetic drive unit that opens and closes the main contact of the vacuum valve of a vacuum electromagnetic contactor, the ambient temperature decreases even when the cause of abnormal heat generation of the electromagnetic solenoid has not been improved. Then, the switch is restored and the coil can be energized, so the electromagnetic solenoid is automatically energized and excited. Therefore, unless the cause of abnormal heat generation is improved, the electromagnetic solenoid repeats excitation and de-excitation. By repeating excitation and de-energization of the electromagnetic solenoid, the main contact of the vacuum valve linked to the electromagnetic solenoid is repeatedly turned on and off. Therefore, the electromagnetic solenoid burnout prevention technique as shown in Patent Document 1 cannot be applied to the vacuum electromagnetic contactor as it is.

  The present invention has been made to solve the above-described problems, and can prevent the electromagnetic solenoid part of the vacuum electromagnetic contactor from being burned due to abnormal heat generation, and can suppress the spread of accidents due to abnormal heat generation. The purpose is to provide a vessel.

  The vacuum electromagnetic contactor according to the present invention is a vacuum electromagnetic contactor comprising an electromagnetic solenoid and a vacuum valve incorporating a pair of contacts that are contacted and separated by excitation of the electromagnetic coil of the electromagnetic solenoid. A shape memory spring that is displaced by the heat generation temperature is arranged in the vicinity of the electromagnetic solenoid, and an abnormality detection switch that is activated by the displacement of the shape memory spring is provided. The abnormality detection switch is activated by the abnormal heat generation and the current to the electromagnetic coil is cut off. In this case, even when the heat generation temperature is lowered, the state of interrupting the current to the electromagnetic coil is maintained.

  According to the vacuum electromagnetic contactor of the present invention, in the vacuum electromagnetic contactor that opens and closes the main contact of the vacuum valve using the driving force of the electromagnetic solenoid, the displacement is caused by the heat generation temperature when the electromagnetic coil of the electromagnetic solenoid abnormally generates heat. A shape memory spring and an abnormality detection switch that operates due to its displacement are provided, and when the abnormality detection switch is activated due to abnormal heat generation, it is configured to maintain the open circuit state even if the heat generation temperature decreases. If the electromagnetic coil heats up abnormally, the excitation of the electromagnetic coil is cut off to prevent damage due to abnormal heat generation, and the abnormality detection switch is not automatically restored, so it can be restored to normal after removing the cause of the abnormality. , Improve safety.

Embodiment 1 FIG.
The present invention will be specifically described below with reference to the drawings.
1 is a cross-sectional view showing a configuration of a vacuum electromagnetic contactor according to Embodiment 1. FIG. As shown in the figure, the vacuum electromagnetic contactor includes a vacuum valve 1 in which a fixed side contact 1a and a movable side contact 1b for turning on and off current are disposed, and a vacuum valve 1 connected to the movable side contact 1b. The insulating rod 2 led out to the outside, the drive lever 4 that rotates around the rotating shaft 3 to drive the insulating rod 2 in the contact / separation direction of the two contacts 1a and 1b, and the rotating shaft 3 are attached to the shaft. A movable element 5 that rotates in conjunction with the drive bar 4 and an electromagnetic solenoid 6 that is installed to face the movable element 5 are provided.
An opening spring (not shown) is provided on the opposite side of the drive lever 4 from the rotating shaft 3 side to bias the movable contact 1b away from the fixed contact 1a. Further, a contact pressure spring 7 is provided between the insulating rod 2 and the drive lever 4 for applying a contact pressure to the movable contact 1b when the vacuum valve 1 is turned on.

The electromagnetic solenoid 6 has a fixed iron core 8 and an electromagnetic coil 9 wound around the fixed iron core 8, and the movable element 5 is attracted to the fixed iron core 8 by exciting the electromagnetic coil 9. It has become.
A shape memory spring 10 made of a shape memory alloy is disposed in the vicinity of the electromagnetic solenoid 6. The characteristics of the shape memory spring 10 will be described later. However, the shape memory spring 10 is displaced in the extending direction due to the heat generation temperature when the electromagnetic coil 9 abnormally generates heat. An abnormality detection switch 11 that is activated by the displacement of the shape memory spring 10 is provided. The abnormality detection switch 11 in FIG. 1 is a b-contact that is closed in a normal state. The electromagnetic coil 9 is connected to a control circuit having a control power source 12 and an external switch 13, but the abnormality detection switch 11 is inserted into this circuit and connected in series to the electromagnetic coil 10.

  An abnormality display lever 14 is provided between the shape memory spring 10 and the abnormality detection switch 11, and when the shape memory spring 10 is extended due to abnormal heat generation, it is pushed by the displacement, and the rotation shaft 15 is shown in the figure. The internal contact 11a of the abnormality detection switch 11 is opened by rotating counterclockwise. That is, the displacement of the shape memory spring 10 is configured to act on the abnormality detection switch 11 via the abnormality display lever 14.

Next, the operation will be described.
FIG. 2 is a diagram for explaining abnormal heat generation of the electromagnetic coil 9 and shows a state in which the abnormality detection switch 11 is activated and both the contacts 1a and 1b of the vacuum valve 1 are cut off. First, the operation of the vacuum valve 1 will be described with reference to the drawings.
The vacuum valve is controlled by an external input command from the shut-off state as shown in FIG. 2 (however, in the normal state, the abnormality display lever 14 is in the normal position as shown in FIG. 1 and the abnormality detection switch 11 is closed). When the external switch 13 of the circuit is turned on and the electromagnetic coil 9 of the electromagnetic solenoid 6 is energized, the mover 5 is attracted to the fixed iron core 8 and rotates counterclockwise. 3, the drive lever 4 rotates counterclockwise. Accordingly, the movable contact 1b is driven upward through the insulating rod 2 to come into contact with the fixed contact 1a, and is pressed by the contact pressure spring 7 to close the circuit, and the vacuum valve 1 is turned on as shown in FIG. become.
When the excitation of the electromagnetic coil 9 is released, the drive lever 4 and the movable element 5 are rotated clockwise by an open spring (not shown), and accordingly, the movable contact 1b is moved downward, and the vacuum valve 1 is shut off. The

  When the electromagnetic solenoid 6 is operating normally, the shape memory spring 10, the abnormality display lever 14, and the abnormality detection switch 11 do not operate and maintain the state as shown in FIG. The tip of is pointing to the normal position. This tip is visible from the outside of the vacuum electromagnetic contactor container (not shown), and if the "normal position" is indicated on the container side, the electromagnetic solenoid 6 operates normally. You can know from outside. The abnormality display lever 14 can be manually operated from the outside.

Next, the case where the electromagnetic coil 9 generates abnormal heat will be described.
For example, when foreign matter is mixed between the electromagnetic solenoid 6 and the mover 5 or when the electromagnetic coil 9 abnormally generates heat due to a control voltage setting error of the electromagnetic coil 9 or the like, the shape memory spring 10 is heated at the generated temperature. Elongate. As a result, the abnormality detection lever 14 rotates counterclockwise about the rotation shaft 15, the abnormality detection switch 11 is pressed, the internal contact 11 a is opened, and the excitation current flowing through the electromagnetic coil 9 of the electromagnetic solenoid 6 is applied. By shutting off, both contacts 1a and 1b of the vacuum valve 1 are shut off as shown in FIG. In this state, the tip of the abnormality detection lever 14 moves downward as shown in FIG. 2 and is in an abnormal position, so an indication that it is “abnormal position” is displayed at this position on the container side. Thus, it can be known from the outside that the electromagnetic solenoid 6 is abnormal.

The shape memory spring 10 has a spring characteristic as shown in FIG. That is, the spring is heated from the normal state a (see reference numeral in the figure) and the high temperature state b (the temperature at which the abnormality detection switch 11 is operated) is set below the maximum operating temperature of the insulator of the electromagnetic coil 9. It is desirable that the stretched state is maintained as long as no external force is applied.
If the cause of abnormal heat generation in the electromagnetic solenoid 6 is removed and the abnormality display lever 14 is manually returned to the normal position, the abnormality detection switch 11 and the shape memory spring 10 are also restored, and the electromagnetic solenoid 6 can be operated again.

In FIGS. 1 and 2 described above, the abnormality detection switch 11 is a normally closed b contact, and when the circuit is pushed by the shape memory spring 10 displaced due to abnormal heat generation, the current to the electromagnetic coil 9 is opened. However, FIG. 4 shows another embodiment. The same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals and the description thereof will be omitted, and only the differences will be described.
In the vacuum electromagnetic contactor shown in FIG. 4, the internal contact 11 b of the abnormality detection switch 11 is an a contact that is open in a normal state, and is connected to the control circuit of the electromagnetic coil 9 via the relay 16. As in the case of FIG. 2, when the electromagnetic coil 9 abnormally heats up for some reason, as shown in FIG. 4, the shape memory spring 10 is extended, and the abnormality display lever 14 is rotated counterclockwise to detect the abnormality detection switch. 11 is closed, and the relay 16 is operated to cut off the current to the control circuit of the electromagnetic coil 9.
Thus, even when the abnormality detection switch 11 is “closed” due to abnormal heat generation, the same effect as in FIGS. In addition, the circuit of the abnormality detection switch for interrupting | blocking the control circuit of an electromagnetic coil at the time of abnormal heat generation is not limited to the structure of FIG.

FIG. 5 shows another embodiment. 1, 2 or 4 differs in the shape of the electromagnetic solenoid and the transmission part of the driving force to the insulating operation rod. The same parts as those in FIGS. 1, 2 or 4 are denoted by the same reference numerals and the description thereof will be omitted, and only the differences will be described.
A mover shaft 18 is slidably provided in a through hole at the center of the fixed iron core 8 so that the mover 17 of the electromagnetic solenoid 6 can contact and separate in the vertical direction with respect to the surface of the opposed fixed iron core 8. And is connected to one end of the insulating rod 2 by a wipe mechanism 19 provided on the tip side thereof. The wipe mechanism 19 is for pressing the contact pressure spring 7 to press the movable contact 1b to the fixed contact 1a when the vacuum valve 1 is turned on.
When the external switch 13 of the control circuit is turned on by the input command from the outside and the electromagnetic coil 9 is excited, the mover 17 is attracted to the fixed iron core 8 and driven upward in the figure, and the wipe mechanism 19 and the insulating rod 2 are driven. As a result, the vacuum valve 1 is turned on as shown in FIG.
When the excitation of the electromagnetic coil 9 is released, the mover 17 moves downward in the figure, and in conjunction with this, the movable contact 1b moves downward and the vacuum valve 1 is shut off.

If the electromagnetic coil 9 is abnormally heated for some reason, the shape memory spring 10 is extended, and the abnormality display lever 14 is rotated counterclockwise about the rotation shaft 15 as a fulcrum. Thereafter, the operation is the same as described with reference to FIG. Thus, even when the current to the electromagnetic coil 9 is interrupted and the heat generation temperature is lowered, the interrupted state is maintained.
Although the internal contact 11a of the abnormality detection switch 11 is illustrated as a b contact, the abnormality detection switch 11 is set to an a contact that is open in a normal state using a relay, similarly to the abnormality detection switch 11 of FIG. When the circuit is closed, the current to the electromagnetic coil 9 may be cut off.

As described above, according to the vacuum electromagnetic contactor of the present embodiment, when the electromagnetic coil abnormally generates heat in the vacuum electromagnetic contactor that opens and closes the main contact of the vacuum valve using the driving force of the electromagnetic solenoid. A shape memory spring that is displaced by the heat generation temperature is placed near the electromagnetic solenoid, and an abnormality detection switch that is activated by the displacement of the shape memory spring is provided. The abnormality detection switch is activated by the abnormal heat generation and the current to the electromagnetic coil is cut off. When the heat generation temperature drops, the current is cut off from the electromagnetic coil so that foreign matter enters between the electromagnetic solenoid and the mover. If the electromagnetic coil overheats abnormally and heats up abnormally due to an incorrect control voltage setting of the electromagnetic coil, etc., the electromagnetic coil excitation is cut off and abnormal heat generation occurs. Damage can be prevented by.
Further, since the automatic return is not performed when the energization of the electromagnetic coil is interrupted, the normal return can be made after removing the cause of the abnormality, and the safety is improved.

  In addition, when the electromagnetic coil is abnormally heated, it is pushed by the displacement of the shape memory spring and rotated from the normal position to the abnormal position, and the abnormality detection switch is operated and the abnormality display lever for indicating the abnormal position is provided. Since the abnormality detection switch is restored by returning it to the normal position, it is possible to recognize the abnormal state at the time of abnormality, and it is possible to reliably return it to normal after removing the cause of the abnormality. The spread of accidents due to abnormal heat generation can be suppressed.

  In addition, the shape memory spring has a temperature characteristic that keeps the displacement even when it is cooled to the vicinity of the outside temperature from the state displaced by the heat generation temperature, and is restored by the return operation of the abnormality display lever. Sometimes, it is possible to prevent troubles such as accidental re-excitation in the process of removing the cause.

  Also, since the current to the electromagnetic coil is cut off when the abnormality detection switch is opened due to abnormal heat generation, the current to the electromagnetic coil can be reduced by connecting the abnormality detection switch in series with the control circuit of the electromagnetic coil. A circuit that cuts off the power can be easily configured.

Furthermore, since the current to the electromagnetic coil is cut off when the abnormality detection switch is closed due to abnormal heat generation, a circuit that cuts off the current to the electromagnetic coil can be configured by using a relay. It can cope with current interruption and can be applied to a wide range of vacuum electromagnetic contactors.

It is sectional drawing which shows the structure of the vacuum electromagnetic contactor by Embodiment 1 of this invention. It is a figure explaining the operation | movement when the electromagnetic coil carries out abnormal heat generation of the vacuum electromagnetic contactor by Embodiment 1 of this invention. It is a figure which shows the characteristic of temperature and spring length of the shape memory spring of FIG. It is sectional drawing which shows the other example of a structure of the vacuum electromagnetic contactor by Embodiment 1 of this invention. It is sectional drawing which shows another example of a structure of the vacuum electromagnetic contactor by Embodiment 1 of this invention. It is principal part sectional drawing which shows the structure of the control valve using the conventional electromagnetic solenoid.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum valve 1a Fixed side contact 1b Movable side contact 2 Insulating rod 3 Rotating shaft 4 Drive lever 5 Movable element 6 Electromagnetic solenoid 7 Contact pressure spring 8 Fixed iron core 9 Electromagnetic coil 10 Shape memory spring 11 Abnormality detection switch 11a, 11b Internal contact 12 Control power supply 13 External switch 14 Abnormal indication lever 15 Rotating shaft 16 Relay 17 Movable element 18 Movable element axis 19 Wipe mechanism.

Claims (5)

In a vacuum electromagnetic contactor comprising an electromagnetic solenoid, and a vacuum valve having a built-in pair of contacts that are contacted and separated by excitation of an electromagnetic coil of the electromagnetic solenoid,
A shape memory spring that is displaced by a heat generation temperature when the electromagnetic coil abnormally generates heat is disposed in the vicinity of the electromagnetic solenoid, and an abnormality detection switch that is operated by the displacement of the shape memory spring is provided. When the electric current to the electromagnetic coil is cut off by operating, the vacuum electromagnetic contactor is configured to maintain the cut-off state of the current to the electromagnetic coil even if the heat generation temperature is lowered .   2. The vacuum electromagnetic contactor according to claim 1, wherein when the electromagnetic coil is abnormally heated, it is pushed by a displacement of the shape memory spring to rotate from a normal position to an abnormal position, and activates the abnormality detection switch. A vacuum electromagnetic contactor comprising an abnormality display lever for indicating a position and returning the abnormality detection switch by returning the abnormality display lever to the normal position.   3. The vacuum electromagnetic contactor according to claim 2, wherein the shape memory spring has a temperature characteristic that maintains the displacement even when it is cooled to near the outside temperature from the state displaced by the heat generation temperature, and the abnormality indication lever is restored. A vacuum electromagnetic contactor that returns by operation.   The vacuum electromagnetic contactor according to any one of claims 1 to 3, wherein the current to the electromagnetic coil is cut off when the abnormality detection switch is opened due to the abnormal heat generation. Features a vacuum electromagnetic contactor.   The vacuum electromagnetic contactor according to any one of claims 1 to 3, wherein when the abnormality detection switch is closed due to the abnormal heat generation, the current to the electromagnetic coil is cut off. Features a vacuum electromagnetic contactor.

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